If the high‑voltage interlock loop (HVIL) is open or mismatched during service, what happens?

If the high‑voltage interlock loop (HVIL) is open or mismatched during service, what happens?

• A. The HV system is automatically de-energized to prevent energizing hazards.
• B. The system remains energized.
• C. It triggers the horn.
• D. It resets the battery management system.

Answer: (A)

When the high-voltage interlock loop is open or mismatched, the safety system treats it as a fault or an unsecured enclosure. The control system then automatically de-energizes the high-voltage network to prevent energizing hazards, so service personnel aren’t exposed to live parts. This fail-safe behavior is built to ensure that opening a service cover or an interlock mismatch cannot leave the high-voltage system energized. The other ideas—keeping power on, sounding a horn, or resetting the battery management system on their own—do not reflect how HVIL is designed to protect people; power is cut until the interlock is properly closed and the system is verified safe.

When the high-voltage interlock loop is open or mismatched, the safety system treats it as a fault or an unsecured enclosure. The control system then automatically de-energizes the high-voltage network to prevent energizing hazards, so service personnel aren’t exposed to live parts. This fail-safe behavior is built to ensure that opening a service cover or an interlock mismatch cannot leave the high-voltage system energized. The other ideas—keeping power on, sounding a horn, or resetting the battery management system on their own—do not reflect how HVIL is designed to protect people; power is cut until the interlock is properly closed and the system is verified safe.